IMPACT OF AREA CLOSURE ON VEGETATION COVER, WOODY SPECIES STRUCTURE AND SOIL CHEMICAL PROPERTIES IN KELALA DALACHA MOUNTAIN, OROMIA, ETHIOPIA

Abstract

This study was undertaken in Kelala Dalacha Mountain in
Oromia, Ethiopia to determine the impacts of ecosystem rehabilitation on
vegetation cover, woody species structure and soil chemical properties. A
random sampling method was used to collect vegetation data from a total of
31 quadrats of 400 m2
each. Four satellite images of the study area,
distributed between 1988 and 2018 were analyzed using Arc GIS software to
assess the Land Use Land Cover (LULC) changes of the area. Composite
sampling was used for soil sample collection and soil was analyzed for
selected chemical properties. Data were analyzed using both descriptive and
inferential statistics. Result indicated that the vegetation cover was 58.1% in
1988, 64.47% in 1998, 80.32% in 2008 and 88.43% in 2018, showing the
positive contribution of area closure in ecosystem rehabilitation. The bare
land in 1988 was changed to either woody species or grasses nowadays.
Similarly, area closure had a positive impact on vegetation structure. Woody
species in the study area displayed an inverted J-shaped pattern of
distribution. The lower DBH classes were found to have relatively higher
number of individuals than that of the middle and the top classes indicating
the importance of area closure. Mean values of soil pH, EC, CEC, OC, TN, P
and K were 6.64, 0.082, 30.92, 2.44, 0.213, 3.91 and 219.38, respectively.
Area closure is a viable strategy for restoring degraded ecosystems as it had
positive impact on vegetation cover, woody species structure and soil
chemical properties. Therefore, it was recommended to ensure wide scale
applications of area closure on all mountains for restoration of ecosystem
function and biodiversity conservation.